The overall goal of this project is to test the immunogenicity of anti-AIDS virus DNA vaccines in newborn rhesus monkeys. Our hope is to find an effective vaccine strategy that could be used eventually to prevent the transmission of AIDS viruses from infected women to their infants. Our first experiment involved testing the immunogenicity of various DNA expression vectors encoding different parts of the genome of a primate AIDS virus. The expression vectors do not contain retroviral transcriptional control elements, and deletions in a key AIDS virus gene have been introduced to avoid generating replication-competent viruses. The DNA vaccines have been given by various routes of administration. We are evaluating the newborn rhesus monkeys for specific antibody responses, and we are also testing whether antiviral cytotoxic T-cell (CTL) responses can be generated. Some newborn monkeys were given the DNA vaccines together with the cytokine IL-12, which favors the developme nt of T-cell immunity. During the past year, we have found that newborn animals can indeed mount specific antibody responses to the DNA vaccines, rather than being made tolerant. These results are promising for the future development of DNA vaccines in neonates. Ultimately, such vaccines may be used to prevent maternal transmission of AIDS viruses.